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The creation and spatial structure of end-linked bimodal polymer networks: a Monte Carlo study 端链双峰聚合物网络的创建和空间结构:蒙特卡罗研究
Polymer Gels and Networks Pub Date : 1997-01-01 Epub Date: 1999-07-07 DOI: 10.1016/S0966-7822(97)00002-6
Christine Hagn, Markus Wittkop, Stefan Kreitmeier, Hans L. Trautenberg, Thomas Hölzl, Dietmar Göritz
{"title":"The creation and spatial structure of end-linked bimodal polymer networks: a Monte Carlo study","authors":"Christine Hagn,&nbsp;Markus Wittkop,&nbsp;Stefan Kreitmeier,&nbsp;Hans L. Trautenberg,&nbsp;Thomas Hölzl,&nbsp;Dietmar Göritz","doi":"10.1016/S0966-7822(97)00002-6","DOIUrl":"10.1016/S0966-7822(97)00002-6","url":null,"abstract":"<div><p>The creation and spatial structure of end-linked bimodal polymer networks was investigated by means of the three-dimensional bond-fluctuation model. The portion of long and short chains was varied. The curing process was found to be reaction-controlled within our simulation parameters. The spatial distribution of the cross-linkers in the created networks revealed no large-scale inhomogeneities. Investigations of the pair-correlation functions of the center of mass of the short chains were consistent with the random distribution of the cross-linkers.</p></div>","PeriodicalId":20331,"journal":{"name":"Polymer Gels and Networks","volume":"5 4","pages":"Pages 327-337"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0966-7822(97)00002-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73228103","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 8
The copolymerisation of tetrahydrofurfuryl methacrylate and methyl methacrylate 甲基丙烯酸四氢糠酰基和甲基丙烯酸甲酯的共聚反应
Polymer Gels and Networks Pub Date : 1996-01-01 Epub Date: 1999-02-11 DOI: 10.1016/0966-7822(96)00008-1
Phuong Y. Ghi , David J.T. Hill , James H. O'Donnell , Peter J. Pomery , Andrew K. Whittaker
{"title":"The copolymerisation of tetrahydrofurfuryl methacrylate and methyl methacrylate","authors":"Phuong Y. Ghi ,&nbsp;David J.T. Hill ,&nbsp;James H. O'Donnell ,&nbsp;Peter J. Pomery ,&nbsp;Andrew K. Whittaker","doi":"10.1016/0966-7822(96)00008-1","DOIUrl":"10.1016/0966-7822(96)00008-1","url":null,"abstract":"<div><p>The bulk copolymerisations of tetrahydrofurfuryl methacrylate, THFMA, and methyl methacrylate, MMA, were carried to low conversion at 60 °C, using benzoyl peroxide, BPO, as the initiator. The compositions of the copolymers were determined using <sup>13</sup>C NMR spectroscopy. The glass transition temperatures of the copolymers were determined using differential scanning calorimetry.</p><p>From the compositional data, the statistical F-test revealed that both the terminal and penultimate models adequately describe the copolymerisation at the 95% confidence level. However, further statistical analysis showed that no significant improvement in fit was evident when considering the penultimate model over the simpler terminal model. Therefore, on the basis of the terminal model, the reactivity ratios were evaluated using a non-linear least squares analysis and were found to be r<sub>T</sub> = 1.06 and r<sub>M</sub>=0.81 for THFMA and MMA, respectively.</p><p>Tacticity splittings of the methyl signal in the <sup>13</sup>C NMR spectra were consistent with the Bernoullian distribution of stereoregularity. The iso-tacticity parameters were found to be <span><math><mtext>δ</mtext><msub><mi></mi><mn>TT</mn></msub><mtext> = 0.24, δ</mtext><msub><mi></mi><mn>MM</mn></msub><mtext> = 0.22 </mtext><mtext>and</mtext><mtext> δ</mtext><msup><mi></mi><mn>∗</mn></msup><mtext>=0.20</mtext></math></span>.</p><p>The glass transition temperatures of the prepared polymers were fitted to the Gordon-Taylor equation and the value of the Gordon-Taylor constant, K, was found to be 1.36 suggesting larger contributions from MMA, compared to THFMA, to the observed glass transition temperatures.</p></div>","PeriodicalId":20331,"journal":{"name":"Polymer Gels and Networks","volume":"4 3","pages":"Pages 253-267"},"PeriodicalIF":0.0,"publicationDate":"1996-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0966-7822(96)00008-1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81721564","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 12
Liquid flow through polymer gels 液体流过聚合物凝胶
Polymer Gels and Networks Pub Date : 1996-01-01 Epub Date: 1999-02-15 DOI: 10.1016/0966-7822(96)00018-4
V. Klepko , Yu. Mel'nichenko , V. Shilov
{"title":"Liquid flow through polymer gels","authors":"V. Klepko ,&nbsp;Yu. Mel'nichenko ,&nbsp;V. Shilov","doi":"10.1016/0966-7822(96)00018-4","DOIUrl":"10.1016/0966-7822(96)00018-4","url":null,"abstract":"<div><p>Slow neutron transmission technique was applied to investigate features of the solvent flow through quasi-porous matrices of gelatin, poly (acrylamide) and silica gels of different concentration/mesh sizes. We find the macromolecular friction coefficient for all gels to be proportional to the concentration of polymer network which correlates well with the predictions of the effective medium approach under the condition of negligible impact of hydrodynamic self-interactions. Determined values of the friction coefficient are used for evaluating the effective mesh sizes, which are in good agreement with the appropriate results of quasi-elastic light scattering for homogeneous poly (acrylamide) gels.</p></div>","PeriodicalId":20331,"journal":{"name":"Polymer Gels and Networks","volume":"4 4","pages":"Pages 351-361"},"PeriodicalIF":0.0,"publicationDate":"1996-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0966-7822(96)00018-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85103679","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 8
Effect of galactomannans on the viscoelastic behaviour of pectin/calcium networks 半乳甘露聚糖对果胶/钙网络粘弹性行为的影响
Polymer Gels and Networks Pub Date : 1996-01-01 Epub Date: 1999-12-09 DOI: 10.1016/0966-7822(95)00018-6
J.A.Lopes da Silva , M.P. Gonçalves , J.L. Doublier , M.A.V. Axelos
{"title":"Effect of galactomannans on the viscoelastic behaviour of pectin/calcium networks","authors":"J.A.Lopes da Silva ,&nbsp;M.P. Gonçalves ,&nbsp;J.L. Doublier ,&nbsp;M.A.V. Axelos","doi":"10.1016/0966-7822(95)00018-6","DOIUrl":"10.1016/0966-7822(95)00018-6","url":null,"abstract":"<div><p>An investigation was carried out on the effect of the addition of galactomannans to pectin/calcium networks with different structural and rheological characteristics. For those pectin/calcium gels characterized by an elastic equilibrium modulus, the addition of the galactomannan increased both the storage and loss moduli, especially at short time scales. This increase was greater than that which could be expected by simple additivity of the viscoelastic properties of each isolated system. The pectin/calcium network remained the continuous gel matrix controlling the viscoelastic behaviour of these systems at low frequency. For pectin/calcium systems close to the sol-gel transition or at low pH, the mixed systems evolved towards the behaviour of viscoelastic liquids in the presence of increasing concentration of the non-gelling polymer. These overall results suggest that there is no specific interaction and that the changes in the rheological properties of the pectin gels are due to galactomannan microphase separation limited by the entrapment of these macromolecules in the pectin-calcium network.</p></div>","PeriodicalId":20331,"journal":{"name":"Polymer Gels and Networks","volume":"4 1","pages":"Pages 65-83"},"PeriodicalIF":0.0,"publicationDate":"1996-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0966-7822(95)00018-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78519196","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 24
Poisson's ratio of polyacrylamide (PAAm) gels 聚丙烯酰胺(PAAm)凝胶泊松比
Polymer Gels and Networks Pub Date : 1996-01-01 Epub Date: 1999-12-09 DOI: 10.1016/0966-7822(95)00013-5
Toshikazu Takigawa , Yoshiro Morino , Kenji Urayama , Toshiro Masuda
{"title":"Poisson's ratio of polyacrylamide (PAAm) gels","authors":"Toshikazu Takigawa ,&nbsp;Yoshiro Morino ,&nbsp;Kenji Urayama ,&nbsp;Toshiro Masuda","doi":"10.1016/0966-7822(95)00013-5","DOIUrl":"10.1016/0966-7822(95)00013-5","url":null,"abstract":"<div><p>Poisson's ratio (<em>μ</em><sub>0</sub>) of polyacrylamide (PAAm) gels was estimated. The value of <em>μ</em><sub>0</sub> for PAAm gels was found to be 0.457, which is close to that for poly (vinyl alcohol) (PVA) gels swollen in the mixture of dimethylsulfoxide (DMSO) and water, but is higher than the value for PVA hydrogels.</p></div>","PeriodicalId":20331,"journal":{"name":"Polymer Gels and Networks","volume":"4 1","pages":"Pages 1-5"},"PeriodicalIF":0.0,"publicationDate":"1996-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0966-7822(95)00013-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81784674","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 95
Pressure dependence on the Flory-Huggins interaction parameter of poly(N-isopropylacrylamide) gels 聚n -异丙基丙烯酰胺凝胶Flory-Huggins相互作用参数的压力依赖性
Polymer Gels and Networks Pub Date : 1996-01-01 Epub Date: 1999-12-09 DOI: 10.1016/0966-7822(96)00022-6
Chikanobu Nakamoto , Tadayoshi Kitada , Eiji Kato
{"title":"Pressure dependence on the Flory-Huggins interaction parameter of poly(N-isopropylacrylamide) gels","authors":"Chikanobu Nakamoto ,&nbsp;Tadayoshi Kitada ,&nbsp;Eiji Kato","doi":"10.1016/0966-7822(96)00022-6","DOIUrl":"https://doi.org/10.1016/0966-7822(96)00022-6","url":null,"abstract":"<div><p>Pressure dependence of the Flory-Huggins interaction parameter for poly (N-isopropylacrylamide)/water gel is obtained by measuring the swelling ratio of the gel in equilibrium under hydrostatic pressure up to about 100 MPa and by employing a mean field theory based on the Flory-type of the Gibbs free energy formula. The interaction parameter strongly depends on the volume fraction of a gel network and also on solvent pressure. In the swollen phase equilibrium of a gel under pressure, both the enthalpy and entropy increase with pressure, the second virial term decreases inversely and the interaction parameter is an increasing function of pressure. It can be seen that hydrostatic compression strengthens the hydrophobic interaction between polymer segments because of a loosening hydrogen-bond structure near the monomer unit.</p></div>","PeriodicalId":20331,"journal":{"name":"Polymer Gels and Networks","volume":"4 1","pages":"Pages 17-31"},"PeriodicalIF":0.0,"publicationDate":"1996-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0966-7822(96)00022-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91659256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 18
About “defects” in networks made by end-linking 关于末端连接造成的网络“缺陷”
Polymer Gels and Networks Pub Date : 1996-01-01 Epub Date: 1999-02-12 DOI: 10.1016/S0966-7822(96)00023-8
C. Rouf-George , J.P. Munch , G. Beinert , F. Isel , A. Pouchelon , J.F. Palierne , F. Boué , J. Bastide
{"title":"About “defects” in networks made by end-linking","authors":"C. Rouf-George ,&nbsp;J.P. Munch ,&nbsp;G. Beinert ,&nbsp;F. Isel ,&nbsp;A. Pouchelon ,&nbsp;J.F. Palierne ,&nbsp;F. Boué ,&nbsp;J. Bastide","doi":"10.1016/S0966-7822(96)00023-8","DOIUrl":"10.1016/S0966-7822(96)00023-8","url":null,"abstract":"<div><p>We studied polydimethylsiloxane networks prepared by end-linking in the bulk. Neutron scattering and scanning light-scattering experiments indicate that the networks swollen with a “good solvent” exhibit rather strong spatial fluctuations of polymer concentration, which are nearly frozen-in. We attribute this effect to the presence of “defects” in the network structure, which is consistent with the results of high frequency rheology measurements, performed on dry networks. The spectrum of static fluctuations appears to be more sensitive to a change in the length of the precusor chains than to the proportion of dangling chains. We propose to explain this result by describing some of the network non-uniformities as fluctuations in the size of the shortest closed circuits along the network.</p></div>","PeriodicalId":20331,"journal":{"name":"Polymer Gels and Networks","volume":"4 5","pages":"Pages 435-450"},"PeriodicalIF":0.0,"publicationDate":"1996-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0966-7822(96)00023-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74288518","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 8
Models for irreversible gel formation 不可逆凝胶形成模型
Polymer Gels and Networks Pub Date : 1996-01-01 Epub Date: 1999-02-12 DOI: 10.1016/S0966-7822(96)00025-1
M. Kolb
{"title":"Models for irreversible gel formation","authors":"M. Kolb","doi":"10.1016/S0966-7822(96)00025-1","DOIUrl":"10.1016/S0966-7822(96)00025-1","url":null,"abstract":"<div><p>Many of the physical and chemical properties of gels are determined by the porosity of the underlying molecular network. The build-up of an infinite network—and even its existence—often depends on irreversible aggregation processes during the earliest stages of structure formation. The system gels only once the primary structures fill space. Aggregation and percolation models each describe one limiting situation of such a sol-gel process. The important intermediate stages cannot be treated with the same degree of generality. New results for this crossover regime are presented: it is shown that there is a smooth change of the structural properties and the cluster size distribution when passing from the aggregation to the gelation stage. The measured fractal dimension of the clusters changes continuously as one approaches the gelation transition.</p></div>","PeriodicalId":20331,"journal":{"name":"Polymer Gels and Networks","volume":"4 5","pages":"Pages 375-382"},"PeriodicalIF":0.0,"publicationDate":"1996-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0966-7822(96)00025-1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77725397","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 6
Improved gel-point predictions using Ahmad-Rolfes-Stepto theory 改进了使用ahmed - rolfes - stepto理论的凝胶点预测
Polymer Gels and Networks Pub Date : 1996-01-01 Epub Date: 1999-02-12 DOI: 10.1016/S0966-7822(96)00020-2
R.F.T. Stepto, D.J.R. Taylor
{"title":"Improved gel-point predictions using Ahmad-Rolfes-Stepto theory","authors":"R.F.T. Stepto,&nbsp;D.J.R. Taylor","doi":"10.1016/S0966-7822(96)00020-2","DOIUrl":"10.1016/S0966-7822(96)00020-2","url":null,"abstract":"<div><p>The predictions of Ahmad-Rolfes-Stepto (ARS) theory in the modelling of gel points are further tested against published data from polyurethane-forming polymerizations. Values of 〈r<sup>2</sup>〉 for the linear sub-chains forming the smallest ring structures based on finite rather than infinite characteristic ratios are used to define the ring-forming parameter required by the theory. The values of 〈r<sup>2</sup>〉 are derived using the results of a recent study of the chain conformational behaviour of polyoxypropylene chains. The gel-point predictions are improved over those obtained previously using infinite characteristic ratios. However, it is deduced that the approximation of linear characteristic ratios with the neglect of branch points and interactions between sequences of different types of chain units will need to be improved.</p></div>","PeriodicalId":20331,"journal":{"name":"Polymer Gels and Networks","volume":"4 5","pages":"Pages 405-414"},"PeriodicalIF":0.0,"publicationDate":"1996-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0966-7822(96)00020-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82511239","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 6
Infrared study of gelatin conformations in the gel and sol states 凝胶和溶胶状态下明胶构象的红外研究
Polymer Gels and Networks Pub Date : 1996-01-01 Epub Date: 1999-02-12 DOI: 10.1016/0966-7822(96)00003-2
D.A. Prystupa, A.M. Donald
{"title":"Infrared study of gelatin conformations in the gel and sol states","authors":"D.A. Prystupa,&nbsp;A.M. Donald","doi":"10.1016/0966-7822(96)00003-2","DOIUrl":"10.1016/0966-7822(96)00003-2","url":null,"abstract":"<div><p>The conformation of gelatin during the gel melting process is monitored by Fourier Transform infrared spectroscopy, and the viability of this methodology for studying gelation is established. Changes are followed in the amide I component peaks, and these are related to conformational changes. The temperature dependence of the component assigned to triple helical segments is in good agreement with a theoretical model of gel melting. Order is still observed to be present above the gel melting temperature and the conformational change occurs gradually through this temperature, with a significant proportion of β-turns persisting in the sol state.</p></div>","PeriodicalId":20331,"journal":{"name":"Polymer Gels and Networks","volume":"4 2","pages":"Pages 87-110"},"PeriodicalIF":0.0,"publicationDate":"1996-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0966-7822(96)00003-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74670423","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 164
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